Dihydropyrrolo[3,2- <i>b</i> ]pyrroles as Novel Conjugated Polymers: Leveraging Simplicity for Sustainability and Student Success

High Resolution Image Download MS PowerPoint Slide Conspectus The field of π-conjugated polymers and molecules has realized tremendous development across numerous technologies due to the ability to easily manipulate macromolecular properties through molecular/monomer design strategies. This synthetic tailorability has led to breakthroughs in power conversion efficiencies (PCEs) for organic photovoltaics (OPVs), maximizing conductivity and switching contrasts for redox-active polymers, and interfacing with aqueous and biological systems. While these achievements are impactful, concepts of green chemistry have often been overlooked, contributing to a trend in which increasing device performance is accompanied by increased synthetic complexity. Researchers studying conjugated polymers have increasingly recognized the importance of synthetic complexity and are exploring simplified structures and preparatory protocols. As such, it will be beneficial for the field to find modular, scalable, and tailorable building blocks that simplify the preparation of conjugated polymers without sacrificing properties and ultimately performance metrics. Early career faculty face numerous challenges especially as it relates to choosing a research topic and nurturing it for success. The PI’s independent research career began in the height of the COVID-19 pandemic which brought on additional challenges and necessitated a flexible approach for engaging students in research with constrained resources. Simultaneously, we were thinking of ways we could impactfully contribute to the field of conjugated polymers and we decided to “keep it simple”. Conjugated scaffolds built around 1,4-dihydropyrrolo[3,2- b ]pyrroles (DHPPs) became a focal point of our efforts because of their reported ease of synthesis and purification but noted tailorability. During our preliminary literature searches we found these DHPPs had only been studied as molecular systems but their attributes were appealing for (1) engaging students with little-to-no experience in meaningful research, (2) launching a new research group with limited resources, and (3) providing the field with a simple building block for conjugated polymers suited for optoelectronic applications. We started our research journey with one question: “ Can DHPPs be designed to participate in polymerizations to create a novel class of tailorable conjugated polymers with reduced synthetic complexity?” This Account highlights our efforts to simplify the synthesis of conjugated polymers, install labile linkages into these simple polymers to facilitate degradability, and establish structure–property relationships to develop DHPPs as high-contrast, color-controlled electrochromic materials. Through these efforts, DHPPs have emerged as useful building blocks to quantifiably reduce synthetic complexity commonly associated with conjugated polymers, create new degradable conjugated polymers, develop novel color-controlled electrochromes, and engage students in meaningful and impactful research. As such, this Account is not only a report on our scientific endeavors but also a reflective exercise that might be useful for other early career faculty, especially those starting at resource-limited institutions, as they initiate independent research programs.